Method and apparatus for HBA migration

ABSTRACT

In one implementation, a system includes multiple SCSI nodes configured to perform a SCSI target function. Each of the multiple SCSI nodes includes a host bus adaptor configured to connect the SCSI node with a Fiber Channel fabric. The host bus adaptor being assigned a world wide name and a network address. The system further includes a host configured to perform a SCSI initiator function. The world wide name assigned to a source host bus adaptor associated with one SCSI node is relocated to a target host bus adaptor associated with another SCSI node. After that, the network address associated with the source host bus adaptor is relocated to the target host bus adaptor. In one implementation, the system determines whether or not a network address assigned to a source host bus adaptor associated with one of the multiple SCSI nodes is shared with at least one other service. If so, the system determined whether the shared network address can be relocated to a target host bus adaptor associated with another one of the multiple of SCSI nodes. If the latter determination is in affirmative, the world wide name and network address are relocated.

CROSS-REFERENCE TO RELATED APPLICATION

This is a Continuation Application of U.S. application Ser. No.12/099,080 filed Apr. 7, 2008. The entire disclosure of the priorapplication is incorporated herein by reference.

DESCRIPTION OF THE INVENTION

1. Field of the Invention

This invention generally relates to storage technology and morespecifically to techniques for host bus adaptor (HBA) migration.

2. Description of the Related Art

Fibre Channel Protocol (FCP) is one of the popular network protocols forbuilding a storage area network (SAN). Host computers with SCSIinitiator function and disk arrays with SCSI target function can beconnected with each other via SAN using FCP. Each node interconnectedvia the FCP incorporates a Host Bus Adaptor (HBA). HBA is a physicalnetwork port connected to SAN. HBA has an associated WWN (World WideName), which is a unique identifier used to interconnect multiple nodesinto the SAN.

The legacy specification of the FCP stipulates that WWN on the HBAcannot be modified and moved to another HBA. For example, WWN_A on HBA_Acannot be moved to another HBA_B. Additionally, each HBA is permitted tohave only one WWN and, therefore, cannot have multiple WWNs. However,newer extensions of the FCP have also been developed. Specifically, NPIV(N_Port ID Virtualization) extension of the FCP eliminates the aforesaidconstraints. The NPIV extension allows one HBA to hold multiple WWNs,and a WWN can be moved to other HBAs. For example, WWN_A on HBA_A can bemoved on other HBA_B (in this case, HBA_A will be assigned other WWNlike WWN_X to avoid duplication of WWNs). With the aforesaid NPIV, ifHBA failure occurs, one can sustain storage I/O connection to disk arraywithout any re-configuration such as without reconfiguration of logicalunit (LUN) security parameters. As it is well known to persons of skillin the art, LUN security configuration uses WWN to control the access toLU from SCSI Initiator.

Other extensions of FCP allow the FCP to be implemented based onEthernet or IP. One such extension is called FC over Ethernet (FCoE) andanother one is called FC over IP (FCIP). For example, the FCoE uses MACaddress to establish connection to the Ethernet based SAN. MAC addressis the unique identifier to connect multiple nodes in Ethernet. Forexample, HBA_A (HBA) has WWN_A (WWN) and MAC_A (MAC address). There isyet another similar protocol called iFCP. The above extensions permitone to develop Ethernet based FC SAN using less complicated Ethernetnetwork switches. Such implementation of the FC SAN is less expensivethan the traditional FC SAN implementation, which uses optical cable andspecialized expensive FC switches.

If an HBA failure occurs in a conventional FC over Ethernet system,WWN_A on HBA_A will be automatically moved to another HBA_B by means ofthe NPIV mechanism. However, according to the conventional technology,the MAC address of the HBA_B remains the same and is not altered uponthe transfer of the WWN. In this case, the connection between HBA_B andthe disk array is established using the MAC address of HBA_B (not MAC_Aof HBA_A). However, because the MAC address of the HBA_A is nottransferred to HBA_B, the services that rely on MAC address of the HBA,as opposed to WWN, such as access control list (ACL), need to bereconfigured after the migration.

In particular, for security reasons, ACL is configured on the networkport of the Ethernet switch. ACL restricts packet/frame transfer usingnetwork identifier such as MAC and IP address and, therefore, it relieson the MAC address and not the WWN. For example, connection betweenMAC_A and MAC_X from/to network port_A can be permitted, but connectionbetween MAC_A and MAC_Y from/to network port_B can be denied by anexemplary ACL configured on Ethernet switch.

This means that one needs to configure individual ACL for each networkport on Ethernet switch (ACL of network port_A and port_B will bedifferent from each other). This will force the user to perform a largenumber configuration updates and result in a substantial downtime of thestorage system. In addition, there is a possibility that WWN migrationwould result in a network access error. The same problem can result fromthe use of the FCIP. In case of the FCIP, the ACL incorporates not onlyMAC address, but also IP address.

Another problem is that re-connection of the FCP layer and the MAC layeroccurs separately. Specifically, the FCP layer does not monitor there-connection process of the MAC layer and the MAC layer does notmonitor the re-connection process of the FCP layer. The FCP layer cannotestablish connection before the re-connection of MAC layer. For example,if the re-connection of the MAC layer is not executed because one hasnot yet properly re-configured the Ethernet switch (but it will be donesoon in the future), and the WWN migration is executed despite thatfact, then the re-connection of FCP will not happen for some time andthe above s condition will be reported as an error.

Thus, new techniques for migration of HBAs are needed.

SUMMARY OF THE INVENTION

The inventive methodology is directed to methods and systems thatsubstantially obviate one or more of the above and other problemsassociated with conventional techniques for migration of HBAs.

In accordance with one aspect of the inventive concept, there isprovided a computerized system including multiple SCSI nodes configuredto perform a SCSI target function. Each of the multiple SCSI nodesincludes a host bus adaptor provided to connect the SCSI node with aFibre Channel fabric. The host bus adaptor is assigned a world wide nameand a network address. The system further includes a host that isconfigured to perform a SCSI initiator function. At least one of themultiple nodes or the host is configured to cause the world wide nameassigned to a source host bus adaptor associated with one of themultiple SCSI nodes to be relocated to a target host bus adaptorassociated with another one of the multiple SCSI nodes. Moreover, atleast one of the multiple nodes or the host is further configured tocause the network address assigned to the source host bus adaptor to berelocated to the target host bus adaptor.

In accordance with another aspect of the inventive concept, there isprovided a computerized system including multiple SCSI nodes configuredto perform a SCSI target function. Each of the multiple SCSI nodesincludes a host bus adaptor provided to connect the SCSI node with aFibre Channel fabric. The host bus adaptor is assigned a world wide nameand a network address. The system further includes a host that isconfigured to perform a SCSI initiator function. At least one of themultiple nodes or the host is configured to determine whether or not thenetwork address assigned to a source host bus adaptor associated withone of the multiple SCSI nodes is shared with at least one other serviceand, if so, if the shared network address can be relocated to a targethost bus adaptor associated with another one of the multiple SCSI nodesand if it is determined that the shared network address can berelocated, to cause the world wide name assigned to the source host busadaptor to be relocated to the target host bus adaptor and the sharednetwork address assigned to the source host bus adaptor to be relocatedto the target host bus adaptor.

In accordance with yet another aspect of the inventive concept, there isprovided a method executed by a system including multiple SCSI nodesincorporating a SCSI target function. Each of the multiple SCSI nodesincludes a host bus adaptor configured to connect the SCSI node with aFibre Channel fabric, the host bus adaptor being assigned a world widename and a network address; and a host incorporating a SCSI initiatorfunction. The method involves relocating a world wide name assigned to asource host bus adaptor associated with one of the multiple SCSI nodesto a target host bus adaptor associated with another one of the multipleSCSI nodes; and relocating the network address assigned to the sourcehost bus adaptor to the target host bus adaptor.

In accordance with a further aspect of the inventive concept, there isprovided a method executed by a system including multiple SCSI nodesincorporating a SCSI target function. Each of the multiple SCSI nodesincludes a host bus adaptor configured to connect the SCSI node with aFibre Channel fabric, the host bus adaptor being assigned a world widename and a network address; and a host incorporating a SCSI initiatorfunction. The method involves determining whether or not a networkaddress assigned to a source host bus adaptor associated with one of themultiple SCSI nodes is shared with at least one other service and, ifso, if the shared network address can be relocated to a target host busadaptor associated with another one of the multiple SCSI nodes; and ifit is determined that the shared network address can be relocated,relocating the world wide name associated with the source host busadaptor to the target host bus adaptor and the shared network addressassigned to the source host bus adaptor to the target host bus adaptor.

In accordance with yet further aspect of the inventive concept, there isprovided a method for assigning a virtual MAC address to a host busadaptor (HBA) of a node. The inventive method involves receiving anaddress request from the node, the address request specifying a worldwide name, the world wide name having been migrated to the node from asecond node; verifying whether the world wide name has already beenassigned the virtual MAC address; verifying whether the address requesthas come from a MAC address included into a MAC consistency group; and,if so, assigning the virtual MAC address, which has already beenassigned to the world wide name.

In accordance with yet further aspect of the inventive concept, there isprovided a method for proposing a virtual MAC address to a Fabric, themethod being performed by a host bus adaptor (HBA) of a node. Theinventive method involves: migrating a world wide name to the node froma second node; verifying whether the world wide name has already beenassigned the virtual MAC address; verifying whether the virtual MACaddress is included into a MAC consistency group; and if so, proposingthe virtual MAC address, which has already been assigned to the worldwide name.

Additional aspects related to the invention will be set forth in part inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. Aspects ofthe invention may be realized and attained by means of the elements andcombinations of various elements and aspects particularly pointed out inthe following detailed description and the appended claims.

It is to be understood that both the foregoing and the followingdescriptions are exemplary and explanatory only and are not intended tolimit the claimed invention or application thereof in any mannerwhatsoever.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification exemplify the embodiments of the presentinvention and, together with the description, serve to explain andillustrate principles of the inventive technique. Specifically:

FIG. 1 illustrates an exemplary system configuration of an embodiment ofthe invention.

FIG. 2 illustrates an exemplary system configuration of an embodiment ofthe invention.

FIG. 3 illustrates an exemplary embodiment of a process for MAC (and IP)address migration together with WWN.

FIG. 4 illustrates an exemplary embodiment of a process for handling afailure at the Step 10020 (WWN migration) of the process shown in FIG.3.

FIG. 5 illustrates an exemplary embodiment of a process for handling afailure at the Step 10030 (MAC (and IP) address migration) of theprocedure shown in FIG. 3.

FIG. 6 illustrates an exemplary embodiment of a process for handling afailure at the Step 10040 (Updating MAC address table and/or ARP table)of the procedure shown in FIG. 3.

FIG. 7 illustrates another implementation of a process for handling afailure at the Step 10040 (Updating MAC address table and/or ARP table).

FIGS. 8 and 9 illustrate an exemplary embodiment of a process forhandling a failure at the Step 10050 (Login to FC Fabric/Port usingHBA_B) of the procedure shown in FIG. 3.

FIG. 10 illustrates an exemplary embodiment of a mapping table 10000between Services (such as FCoE, iSCSI . . . ), IP address, MAC addressand WWN.

FIG. 11 illustrates an exemplary embodiment of the migration processcorresponding to a situation in which the MAC address to be migrated isused by only one WWN (NPIV).

FIG. 12 illustrates an exemplary embodiment of the migration processcorresponding to a situation in which the MAC address to be migrated isshared by other services (such as other WWN).

FIG. 13 illustrates an exemplary embodiment of the migration processcorresponding to a situation in which the MAC address to be migrated isshared by other IP address(es).

FIG. 14 illustrates an exemplary embodiment of the migration processcorresponding to a configuration in which the device, which migrates theWWN and the MAC/IP, is a SCSI target device.

FIG. 15 illustrates one exemplary embodiment of the MAC addressassignment mechanism corresponding to a configuration utilizing theFCoE.

FIG. 16 illustrates an exemplary procedure for migrating WWN and V-MACaddresses.

FIG. 17 illustrates an exemplary flowchart corresponding to theprocedure for migrating WWN and V-MAC addresses.

FIG. 18 shows another exemplary configuration, wherein that multipleHBAs share the MAC Consistency Group Table.

FIG. 19 illustrates an exemplary flowchart of the procedure formigrating WWN and V-MAC addresses.

FIG. 20 illustrates an exemplary embodiment of a computer platform uponwhich the inventive system may be implemented.

DETAILED DESCRIPTION

In the following detailed description, reference will be made to theaccompanying drawings, in which identical functional elements aredesignated with like numerals. The aforementioned accompanying drawingsshow by way of illustration, and not by way of limitation, specificembodiments and implementations consistent with principles of thepresent invention. These implementations are described in sufficientdetail to enable those skilled in the art to practice the invention andit is to be understood that other implementations may be utilized andthat structural changes and/or substitutions of various elements may bemade without departing from the scope and spirit of present invention.The following detailed description is, therefore, not to be construed ina limited sense. Additionally, the various embodiments of the inventionas described may be implemented in the form of a software running on ageneral purpose computer, in the form of a specialized hardware, orcombination of software and hardware.

FIGS. 1 and 2 illustrate an exemplary system configuration of anembodiment of the invention. An exemplary embodiment of the inventivesystem may incorporate one or more of the following components: DiskArray System 1000; Host computer 2000; Management server 3000; andEthernet/IP network 4000.

The Disk Array System 3000 incorporates a functionality of a SCSI targetsystem. It may incorporate a Host Bus Adapter (HBA) 1010/1040, whichhandles network I/O operations, which may be performed under FCP andEthernet protocols, a Storage controller 1020, which acts as a RAID(Redundant Arrays of Inexpensive Disks) controller handling disk I/O,and LU (Logical Unit) 1030, which is composed of multiple Hard DiskDrives (HDDs).

The Host computer 2000 incorporates a CPU, a memory, an HBA, as well asthe other appropriate components (not shown) necessary for itsoperation. The Host computer 2000 runs an Operation System (OS) as wellas various user applications. In one embodiment of the invention, theHost computer 2000 functions as a SCSI initiator. The Management server3000 incorporates a CPU, a memory, an HBA as well as the otherappropriate components (not shown) necessary for its operation. TheManagement server 3000 executes an Operation System (OS) as well asother applications. The Network 4000 incorporates an Ethernet switch,which is configured to transfer Ethernet frames from/to its networkports.

The HBA 1010/1040 is assigned a World Wide Name (WWN), a MAC address andan IP address, all of which are unique identifiers. These uniqueidentifiers are used to interconnect multiple HBAs on the Ethernetnetwork or Fibre Channel Protocol (FCP).

Exemplary Process of WWN/MAC/IP Migration

In accordance with an embodiment of the inventive concept, there areseveral situations when the MAC (and IP) address are migrated togetherwith the WWN: 1: MAC (and IP) address and WWN migration completed; 2:WWN migration failure occur; 3: MAC (and IP) address migration failureoccur; and 4: MAC (and IP) address and WWN migration completed, but FCPlogin failure.

FIG. 3 illustrates an exemplary embodiment of a process for MAC (and IP)address migration together with WWN. First, the HBA_A logout from FCFabric is performed using LOGO request (Step 10010). After that, theHBA_A attempts to move its WWN_A to another HBA_B (Step 10020). If thetransfer of the WWN_A succeeds, HBA_A attempts to move its MAC (and IP)address (MAC_A, IP_A) to HBA_B (Step 10030). After the migration of theMAC_A (and IP_A) to HBA_B, the MAC address table of Ethernet switch andARP table (Address Resolution Protocol (Mapping information of MACaddress and IP address)) of other nodes must be updated accordingly.Therefore, the HBA_B waits for the update of this information. Thisupdate procedure can be implemented by sending a blank MAC frame tochange information in the MAC address table and GARP (Gratuitous ARP)packet to change the information in the ARP table of each node (Step10040). When MAC/IP layer network connection is established, HBA_Battempts to login to the FC Fabric/Port using FDISC/PLOGI requests (Step10050).

FIG. 4 illustrates an exemplary embodiment of a process for handling afailure at the Step 10020 (WWN migration) of the process shown in FIG.3. If such failure occurs, the HBA_A repeats the WWN move attemptseveral times (Step 10021). When all attempts fail and the HBA_Adetermines that the WWN cannot be moved to the HBA_B, the HBA_A willgive up on the WWN migration, and subsequently re-login to FCFabric/Port using HBA_A (Step 10022).

FIG. 5 illustrates an exemplary embodiment of a process for handling afailure at the Step 10030 (MAC (and IP) address migration) of theprocedure shown in FIG. 3. If such failure occurs, the HBA_A repeats theMAC (and IP) address move attempt several times (Step 10031). When allattempts fail and the HBA_B determines that the MAC (and IP) addresscannot be moved to the HBA_B, the HBA_A will give up on the MAC (and IP)address migration, and will subsequently attempt to return WWN_A onHBA_B to HBA_A (Step 10032). After that, the HBA_A logins to FCFabric/Port, without migrating WWN to HBA_B (Step 10033).

FIG. 6 illustrates an exemplary embodiment of a process for handling afailure at the Step 10040 (Updating MAC address table and/or ARP table)of the procedure shown in FIG. 3. If such failure occurs, the HBA_A andthe HBA_B repeat the attempts to update the MAC address table and/or theARP table several times (Step 10041). When all attempts fail and the MACaddress table and/or the ARP table cannot be updated, the HBA_A and theHBA_B give up on the MAC (and IP) address migration. Subsequently, theHBA_B logins to the FC Fabric/Port using another MAC (and IP) addressassigned to HBA_B (Step 10042). However, in this case, the MAC (and IP)address will be changed. FIG. 7 illustrates another implementation ofthis process. Before login into the FC Fabric/Port, the HBA_B tries toreturn the WWN_A on the HBA_B to the HBA_A (Step 10043). After that, theHBA_A logins into the FC Fabric/Port, without migrating the WWN to theHBA_B (Step 10044).

FIGS. 8 and 9 illustrate an exemplary embodiment of a process forhandling a failure at the Step 10050 (Login to FC Fabric/Port usingHBA_B) of the procedure shown in FIG. 3. If such failure occurs, theHBA_B repeats several times the re-login attempts to the FC Fabric/Port(Step 10051). When all the re-login attempts fail, the HBA_B gives up onthe login procedure and subsequently attempts to return the related MAC(and IP) address and the WWN to the HBA_A (Step 10054). After that, theHBA_A logins into the FC Fabric/Port, without migrating WWN to HBA_B(Step 10055).

The above-described procedures can be executed by HBA, Computing Node(such as Disk Array System 1000, Host 2000, and Ethernet switch onnetwork 4000. And Management server 3000 can coordinate these processesbetween plural components).

Process of WWN/MAC/IP Migration and Other Services

In accordance with an embodiment of the invention, when MAC (and IP)address can be shared between WWN (NPIV) and the other services such asiSCSI, one needs to determine whether or not this shared MAC (and IP)address can be migrated. There are several possible situations: 1: MACaddress to be migrated is used by only WWN (NPIV); 2: MAC address to bemigrated is shared by other services; and 3: MAC address to be migratedis used by other IP address.

FIG. 10 illustrates an exemplary embodiment of a mapping table 10000between Services (such as FCoE, iSCSI . . . ), IP address, MAC addressand WWN. For example, FCoE service uses MAC address 11:11:11:11:11:11and WWN 10:10:10:10:10:10:10:11. FCoE service and iSCSI service shareMAC address 22:22:22:22:22:22. Finally, the two FCoE services share MACaddress 44:44:44:44:44:44.

FIG. 11 illustrates an exemplary embodiment of the migration processcorresponding to a situation in which the MAC address to be migrated isused by only one WWN (NPIV). After the Step 10010, described above, theHBA_A locates the MAC address associated with the WWN to be migrated(Step 10060). Next, the HBA_A attempts to locate other services sharingthis MAC address using the mapping table 10000 (Step 10070). If thereare no such other services, the HBA_A attempts to find an IP addressassociated with this MAC address from the mapping table 10000 (Step10080). If there is no such IP address, the HBA_A proceeds to Step 10030to migrate the WWN and the MAC address.

FIG. 12 illustrates an exemplary embodiment of the migration processcorresponding to a situation in which the MAC address to be migrated isshared by other services (such as other WWN). In this case, the HBA_Afirst determines whether or not the other services sharing that MACaddress are movable. For example, the mapping table 10000 has theinformation that indicates whether or not each service is movable (Step10071). If the service is not movable, the HBA_A will login into the FCFabric/Port, without migrating the WWN to the HBA_B (Step 10072).

FIG. 13 illustrates an exemplary embodiment of the migration processcorresponding to a situation in which the MAC address to be migrated isshared by other IP address(es). In this case, the HBA_A determineswhether or not this IP address(es) is movable. For example, the mappingtable 10000 has the information that indicates whether or not eachservice can be moved (Step 10081). If the service is not movable, theHBA_A will login into the FC Fabric/Port, without migrating the WWN tothe HBA_B (Step 10082). The above-described processes can be executed byHBA, Computing Node (such as Disk Array System 1000, Host 2000, andEthernet switch on network 4000. And Management server 3000 cancoordinate these processes between plural components).

FIG. 14 illustrates an exemplary embodiment of the migration processcorresponding to a configuration in which the device, which migrates theWWN and the MAC/IP, is a SCSI target device. As well know to persons ofordinary skill in the art, a target is the storage-device side endpointof a SCSI session. SCSI initiators request data transfers from SCSItargets. SCSI targets are typically disk-drives, tape-drives, optical,or other media devices.

The procedure shown in FIG. 14 allows SCSI target to migrate MAC/IPaddress by the NPIV, described hereinabove. The procedure shown in FIG.14 is slightly different from the above-described procedurescorresponding to SCSI initiator devices. Specifically, if failure ofHBA_A is detected, the SCSI target device will try to move its WWN tothe other HBA_B, see step 10090. After that, at step 10091, the SCSItarget device will try to migrate MAC/IP address to the HBA_B. At step10092, the device will attempt to establish MAC/IP layer connection.Finally, at step 10093, it will try to login to FC Fabric and wait forthe login access from the corresponding SCSI initiator.

In the above-described example, the SCSI initiator device will act asfollows. When the failure of HBA_A of SCSI target, SCSI initiator willtry to logout from this port. After logout procedure, it will try tore-login into the FC Fabric and get the SCSI target information. Whenthe SCSI initiator device obtains SCSI target information (WWN onHBA_B), it will try to login to HBA_B.

The above-described embodiments of the inventive system can be adoptedfor a configuration wherein the MAC address is assigned statically intoeach of the multiple HBAs. However, in other system configurations, theMAC address used for storage I/O traffic can be assigned dynamicallyusing Fabric Service such as FCoE.

FIG. 15 illustrates one exemplary embodiment of the MAC addressassignment mechanism corresponding to a configuration utilizing theFCoE. When HBA-A 1501 sends FLOGI message 1502 to Fabric 1503 (thistime, static MAC-A 1508 will be used), this message 1502 has WWN (WWN-A)1506 and proposed MAC address (MAC-A1) 1507, which is Virtual MACaddress for FCoE I/O traffic. Ordinary, proposed V-MAC address will beapproved by Fabric by means of the FLOGI response message 1504. Afterthis process, HBA A 1505 starts FCoE I/O communication with another node(for example, HBA-B 1505) by using V-MAC address.

FIG. 16 illustrates an exemplary procedure for migrating WWN and V-MACaddresses in the above configuration. When WWN-A 1603 is moved to HBA-B1505, MAC-A1 1604 should be moved to HBA-B 1505, as well. However, whenHBA-B 1505 sends FLOGI message 1601 to the Fabric 1503, it will proposethe MAC-B1 address 1605. This request will let the Fabric 1503 assignMAC-B1 address to HBA-B 1505 and not MAC-A1. To prevent this, the Fabric1503 incorporates a MAC Consistency Group Table 1606. It allows theFabric 1503 to determine which MAC address should be assigned to the HBAwhen the FLOGI message 1601 comes in. For instance, the MAC-A1 address1604 was assigned when the FLOGI of WWN-A occurred. The migration of theWWN-A 1501 will cause another FLOGI operation (1601, 1602) to beinitiated from the HBA-B 1505. If new FLOGI message 1601 from the HBA-B1505 comes to the Fabric 1503, the Fabric checks the source MAC address(MAC-B 1605) and WWN included FLOGI message 1601 (WWN-A 1603) and theMAC Consistency Group Table 1606. Because the WWN-A 1603 is alreadyassociated with MAC-A1 1604, the Fabric will assign MAC-A1 1604 to HBA-B1505, instead of MAC-B1 1607.

FIG. 17 illustrates an exemplary flowchart corresponding to the aboveprocess. The operation of the process starts at step 1701. At step 1702,the Fabric 1503 receives a FLOGI request from the HBA associated withthe WWN-A address. At step 1703, the Fabric checks the MAC ConsistencyGroup Table 1606 whether WWN-A has already been assigned a V-MACaddress. If so, the operation proceeds to step 1705. If no, theoperation proceeds to step 1704. At step 1705, the Fabric checks whetherthe request came from an entity associated with a MAC address includedin a MAC Consistency Group. If so, the Fabric assigns to the requestorthe same V-MAC address, which has already been assigned to WWN-A.Otherwise, the operation proceeds to step 1704, whereupon the proposedMAC address is assigned to the requestor. The operation terminates atstep 1707.

FIG. 18 shows another exemplary configuration, wherein that multipleHBAs share the MAC Consistency Group Table 1801. When the migrationoccurs, HBA-B 1505 will propose the assigned MAC address (MAC-A1 1604),instead of the MAC-B1 1607.

FIG. 19 illustrates an exemplary flowchart of the above process. Theoperation of the process starts at step 1901. At step 1902, the HBA-Bperforms the move of the WWN-A address and prepares to send a FLOGIrequest to the Fabric. At step 1903, the HBA-B checks the MACConsistency Group Table 1801 whether WWN-A has already been assigned aV-MAC address. If so, the operation proceeds to step 1905. Otherwise,the operation proceeds to step 1904. At step 1905, the HBA-B checkswhether the MAC address is included in a MAC Consistency Group. If so,the HBA-B proposes to the Fabric in the FLOGI request the same V-MACaddress, which has already been assigned to WWN-A. Otherwise, theoperation proceeds to step 1904, whereupon the V-MAC address is proposedto the Fabric in an ordinary manner. The operation terminates at step1907. The above process allows the Fabric to assign same V-MAC addressto HBA-B.

Exemplary Computer Platform

FIG. 15 is a block diagram that illustrates an embodiment of acomputer/server system 1400 upon which an embodiment of the inventivemethodology may be implemented. The system 1400 includes acomputer/server platform 1401, peripheral devices 1402 and networkresources 1403.

The computer platform 1401 may include a data bus 1404 or othercommunication mechanism for communicating information across and amongvarious parts of the computer platform 1401, and a processor 1405coupled with bus 1401 for processing information and performing othercomputational and control tasks. Computer platform 1401 also includes avolatile storage 1406, such as a random access memory (RAM) or otherdynamic storage device, coupled to bus 1404 for storing variousinformation as well as instructions to be executed by processor 1405.The volatile storage 1406 also may be used for storing temporaryvariables or other intermediate information during execution ofinstructions by processor 1405. Computer platform 1401 may furtherinclude a read only memory (ROM or EPROM) 1407 or other static storagedevice coupled to bus 1404 for storing static information andinstructions for processor 1405, such as basic input-output system(BIOS), as well as various system configuration parameters. A persistentstorage device 1408, such as a magnetic disk, optical disk, orsolid-state flash memory device is provided and coupled to bus 1401 forstoring information and instructions.

Computer platform 1401 may be coupled via bus 1404 to a display 1409,such as a cathode ray tube (CRT), plasma display, or a liquid crystaldisplay (LCD), for displaying information to a system administrator oruser of the computer platform 1401. An input device 1410, includingalphanumeric and other keys, is coupled to bus 1401 for communicatinginformation and command selections to processor 1405. Another type ofuser input device is cursor control device 1411, such as a mouse, atrackball, or cursor direction keys for communicating directioninformation and command selections to processor 1404 and for controllingcursor movement on display 1409. This input device typically has twodegrees of freedom in two axes, a first axis (e.g., x) and a second axis(e.g., y), that allows the device to specify positions in a plane.

An external storage device 1412 may be connected to the computerplatform 1401 via bus 1404 to provide an extra or removable storagecapacity for the computer platform 1401. In an embodiment of thecomputer system 1400, the external removable storage device 1412 may beused to facilitate exchange of data with other computer systems.

The invention is related to the use of computer system 1400 forimplementing the techniques described herein. In an embodiment, theinventive system may reside on a machine such as computer platform 1401.According to one embodiment of the invention, the techniques describedherein are performed by computer system 1400 in response to processor1405 executing one or more sequences of one or more instructionscontained in the volatile memory 1406. Such instructions may be readinto volatile memory 1406 from another computer-readable medium, such aspersistent storage device 1408. Execution of the sequences ofinstructions contained in the volatile memory 1406 causes processor 1405to perform the process steps described herein. In alternativeembodiments, hard-wired circuitry may be used in place of or incombination with software instructions to implement the invention. Thus,embodiments of the invention are not limited to any specific combinationof hardware circuitry and software.

The term “computer-readable medium” as used herein refers to any mediumthat participates in providing instructions to processor 1405 forexecution. The computer-readable medium is just one example of amachine-readable medium, which may carry instructions for implementingany of the methods and/or techniques described herein. Such a medium maytake many forms, including but not limited to, non-volatile media,volatile media, and transmission media. Non-volatile media includes, forexample, optical or magnetic disks, such as storage device 1408.Volatile media includes dynamic memory, such as volatile storage 1406.Transmission media includes coaxial cables, copper wire and fiberoptics, including the wires that comprise data bus 1404. Transmissionmedia can also take the form of acoustic or light waves, such as thosegenerated during radio-wave and infra-red data communications.

Common forms of computer-readable media include, for example, a floppydisk, a flexible disk, hard disk, magnetic tape, or any other magneticmedium, a CD-ROM, any other optical medium, punchcards, papertape, anyother physical medium with patterns of holes, a RAM, a PROM, an EPROM, aFLASH-EPROM, a flash drive, a memory card, any other memory chip orcartridge, a carrier wave as described hereinafter, or any other mediumfrom which a computer can read.

Various forms of computer readable media may be involved in carrying oneor more sequences of one or more instructions to processor 1405 forexecution. For example, the instructions may initially be carried on amagnetic disk from a remote computer. Alternatively, a remote computercan load the instructions into its dynamic memory and send theinstructions over a telephone line using a modem. A modem local tocomputer system 1400 can receive the data on the telephone line and usean infra-red transmitter to convert the data to an infra-red signal. Aninfra-red detector can receive the data carried in the infra-red signaland appropriate circuitry can place the data on the data bus 1404. Thebus 1404 carries the data to the volatile storage 1406, from whichprocessor 1405 retrieves and executes the instructions. The instructionsreceived by the volatile memory 1406 may optionally be stored onpersistent storage device 1408 either before or after execution byprocessor 1405. The instructions may also be downloaded into thecomputer platform 1401 via Internet using a variety of network datacommunication protocols well known in the art.

The computer platform 1401 also includes a communication interface, suchas network interface card 1413 coupled to the data bus 1404.Communication interface 1413 provides a two-way data communicationcoupling to a network link 1414 that is connected to a local network1415. For example, communication interface 1413 may be an integratedservices digital network (ISDN) card or a modem to provide a datacommunication connection to a corresponding type of telephone line. Asanother example, communication interface 1413 may be a local areanetwork interface card (LAN NIC) to provide a data communicationconnection to a compatible LAN. Wireless links, such as well-known802.11a, 802.11b, 802.11g and Bluetooth may also used for networkimplementation. In any such implementation, communication interface 1413sends and receives electrical, electromagnetic or optical signals thatcarry digital data streams representing various types of information.

Network link 1413 typically provides data communication through one ormore networks to other network resources. For example, network link 1414may provide a connection through local network 1415 to a host computer1416, or a network storage/server 1417. Additionally or alternatively,the network link 1413 may connect through gateway/firewall 1417 to thewide-area or global network 1418, such as an Internet. Thus, thecomputer platform 1401 can access network resources located anywhere onthe Internet 1418, such as a remote network storage/server 1419. On theother hand, the computer platform 1401 may also be accessed by clientslocated anywhere on the local area network 1415 and/or the Internet1418. The network clients 1420 and 1421 may themselves be implementedbased on the computer platform similar to the platform 1401.

Local network 1415 and the Internet 1418 both use electrical,electromagnetic or optical signals that carry digital data streams. Thesignals through the various networks and the signals on network link1414 and through communication interface 1413, which carry the digitaldata to and from computer platform 1401, are exemplary forms of carrierwaves transporting the information.

Computer platform 1401 can send messages and receive data, includingprogram code, through the variety of network(s) including Internet 1418and LAN 1415, network link 1414 and communication interface 1413. In theInternet example, when the system 1401 acts as a network server, itmight transmit a requested code or data for an application programrunning on client(s) 1420 and/or 1421 through Internet 1418,gateway/firewall 1417, local area network 1415 and communicationinterface 1413. Similarly, it may receive code from other networkresources.

The received code may be executed by processor 1405 as it is received,and/or stored in persistent or volatile storage devices 1408 and 1406,respectively, or other non-volatile storage for later execution. In thismanner, computer system 1401 may obtain application code in the form ofa carrier wave.

It should be noted that the present invention is not limited to anyspecific firewall system. The inventive policy-based content processingsystem may be used in any of the three firewall operating modes andspecifically NAT, routed and transparent.

Finally, it should be understood that processes and techniques describedherein are not inherently related to any particular apparatus and may beimplemented by any suitable combination of components. Further, varioustypes of general purpose devices may be used in accordance with theteachings described herein. It may also prove advantageous to constructspecialized apparatus to perform the method steps described herein. Thepresent invention has been described in relation to particular examples,which are intended in all respects to be illustrative rather thanrestrictive. Those skilled in the art will appreciate that manydifferent combinations of hardware, software, and firmware will besuitable for practicing the present invention. For example, thedescribed software may be implemented in a wide variety of programmingor scripting languages, such as Assembler, C/C++, perl, shell, PHP,Java, etc.

Moreover, other implementations of the invention will be apparent tothose skilled in the art from consideration of the specification andpractice of the invention disclosed herein. Various aspects and/orcomponents of the described embodiments may be used singly or in anycombination in the computerized storage system with HBA migrationfunctionality. It is intended that the specification and examples beconsidered as exemplary only, with a true scope and spirit of theinvention being indicated by the following claims.

1. A method for migrating a world wide name from a first host busadaptor to a second host bus adaptor comprising: said first host busadaptor receiving I/O operations from a host computer by a SCSI commandand transferring the command to a storage controller coupled to astorage device, said first host bus adaptor associated with said worldwide name and a MAC address; relocating said world wide name from saidfirst host bus adaptor to said second host bus adaptor; determining, bya processor, whether or not said MAC address associated with said firsthost bus adaptor can be relocated to said second host bus adaptor;relocating said MAC address from said first host bus adaptor to saidsecond host bus adaptor if said determining is positive; giving up onsaid MAC address relocation if said determining is negative; and whereinsaid second host bus adaptor receives I/O operations from a hostcomputer by a SCSI command and transfers the command to a storagecontroller coupled to a storage device, after said second host busadaptor is associated with said world wide name and said MAC address, ifsaid MAC address is relocated to said second host bus adaptor.
 2. Themethod according to claim 1, wherein said determining is performed bywhether said MAC address is shared by other services.
 3. The methodaccording to claim 1, wherein said determining is performed by referringto a table including an information of whether the MAC address isincluded in a consistency group.
 4. The method according to claim 1,further comprising: establishing MAC layer connection after saidrelocating said MAC address from said first host bus adaptor to saidsecond host bus adaptor; wherein said determining is performed bywhether said MAC address is shared by other services.
 5. The methodaccording to claim 4, wherein said storage devices are Hard Disk Drivesand said storage controller configures said storage devices in a RAIDarray.
 6. The method according to claim 2, wherein said world wide nameand said MAC address are both unique identifiers.
 7. The methodaccording to claim 6, wherein said first and second host bus adaptorhandles network operations performed under Fibre Channel protocol andEthernet protocol, and said relocating of said world wide name isperformed by NPIV technology.
 8. A method for migrating a world widename from a first host bus adaptor to a second host bus adaptorcomprising: said first host bus adaptor receiving I/O operations from ahost computer by a SCSI command and transferring the command to astorage controller coupled to a storage device, said first host busadaptor associated with said world wide name and a MAC address;determining, by a processor, whether or not said MAC address associatedwith said first host bus adaptor can be relocated to said second hostbus adaptor; relocating said world wide name from said first host busadaptor to said second host bus adaptor if said determining is positive;relocating said MAC address from said first host bus adaptor to saidsecond host bus adaptor if said determining is positive; giving up onsaid MAC address relocation if said determining is negative; and whereinsaid second host bus adaptor receives I/O operations from a hostcomputer by a SCSI command and transfers the command to a storagecontroller coupled to a storage device, after said second host busadaptor is associated with said world wide name and said MAC address, ifsaid MAC address is relocated to said second host bus adaptor.
 9. Themethod according to claim 8, wherein said determining is performed bywhether said MAC address is shared by other services.
 10. The methodaccording to claim 8, wherein said determining is performed by referringto a table including an information of whether the MAC address isincluded in a consistency group.
 11. The method according to claim 8,further comprising: establishing MAC layer connection after saidrelocating said MAC address from said first host bus adaptor to saidsecond host bus adaptor; wherein said determining is performed bywhether said MAC address is shared by other services.
 12. The methodaccording to claim 11, wherein said storage devices are Hard Disk Drivesand said storage controller configures said storage devices in a RAIDarray.
 13. The method according to claim 9, wherein said world wide nameand said MAC address are both unique identifiers.
 14. The methodaccording to claim 13, wherein said first and second host bus adaptorhandles network operations performed under Fibre Channel protocol andEthernet protocol, and said relocating of said world wide name isperformed by NPIV technology.